1 files changed, 101 insertions, 0 deletions
diff --git a/usb/include/pixelusb/MonitorFfs.h b/usb/include/pixelusb/MonitorFfs.h
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+++ b/usb/include/pixelusb/MonitorFfs.h
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+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef HARDWARE_GOOGLE_PIXEL_USB_MONITORFFS_H_
+#define HARDWARE_GOOGLE_PIXEL_USB_MONITORFFS_H_
+
+#include <android-base/unique_fd.h>
+#include <pixelusb/CommonUtils.h>
+
+#include <mutex>
+#include <string>
+#include <thread>
+#include <vector>
+
+namespace android {
+namespace hardware {
+namespace google {
+namespace pixel {
+namespace usb {
+
+using ::android::base::unique_fd;
+
+// MonitorFfs automously manages gadget pullup by monitoring
+// the ep file status. Restarts the usb gadget when the ep
+// owner restarts.
+class MonitorFfs {
+  private:
+    // Monitors the endpoints Inotify events.
+    unique_fd mInotifyFd;
+    // Control pipe for shutting down the mMonitor thread.
+    // mMonitor exits when SHUTDOWN_MONITOR is written into
+    // mEventFd/
+    unique_fd mEventFd;
+    // Pools on mInotifyFd and mEventFd.
+    unique_fd mEpollFd;
+    std::vector<int> mWatchFd;
+
+    // Maintains the list of Endpoints.
+    std::vector<std::string> mEndpointList;
+    // protects the CV.
+    std::mutex mLock;
+    std::condition_variable mCv;
+    // protects mInotifyFd, mEpollFd.
+    std::mutex mLockFd;
+
+    // Flag to maintain the current status of gadget pullup.
+    bool mCurrentUsbFunctionsApplied;
+
+    // Thread object that executes the ep monitoring logic.
+    std::unique_ptr<std::thread> mMonitor;
+    // Callback to be invoked when gadget is pulled up.
+    void (*mCallback)(bool functionsApplied, void *payload);
+    void *mPayload;
+    // Name of the USB gadget. Used for pullup.
+    const char *const mGadgetName;
+    // Monitor State
+    bool mMonitorRunning;
+
+  public:
+    MonitorFfs(const char *const gadget);
+    // Inits all the UniqueFds.
+    void reset();
+    // Starts monitoring endpoints and pullup the gadget when
+    // the descriptors are written.
+    bool startMonitor();
+    // Waits for timeout_ms for gadget pull up to happen.
+    // Returns immediately if the gadget is already pulled up.
+    bool waitForPullUp(int timeout_ms);
+    // Adds the given fd to the watch list.
+    bool addInotifyFd(std::string fd);
+    // Adds the given endpoint to the watch list.
+    void addEndPoint(std::string ep);
+    // Registers the async callback from the caller to notify the caller
+    // when the gadget pull up happens.
+    void registerFunctionsAppliedCallback(void (*callback)(bool functionsApplied, void *(payload)),
+                                          void *payload);
+    bool isMonitorRunning();
+    // Ep monitoring and the gadget pull up logic.
+    static void *startMonitorFd(void *param);
+};
+
+}  // namespace usb
+}  // namespace pixel
+}  // namespace google
+}  // namespace hardware
+}  // namespace android
+
+#endif  // HARDWARE_GOOGLE_PIXEL_USB_MONITORFFS_H_